Mr Kilani was detained this month on a charge of inciting police to break the law.
The judge did not give a reason for the decision. A trial date has not been announced.
Last summer, Mr Saied suspended parliament and seized most powers in a move his opponents described as a coup. He also changed the supreme judicial council, reinforcing his rule.
Mr Kilani’s arrest angered human rights groups at home and abroad. They accused Mr Saied of imposing a dictatorial regime and using the military and judiciary against his opponents.
Mr Saied rejected accusations and said he did not interfere in the judiciary.
On Monday, Mr Saied said in a televised address that Tunisians were free to express their views on a new political system for their country.
A referendum on constitutional changes is scheduled for July.
Mr Saied spoke after about 2,000 people protested in the capital, Tunis, on Sunday, calling for greater political rights and the return of a multiparty government.
“Work will continue to go to a referendum on July 25, after which everyone will be involved in expressing their opinions and suggestions for the new political system,” he said.